OFDM systems are known to have high peak to average power ratios (PAPR) as compared to single carrier systems. Having a higher PAPR may ultimately be detrimental to the efficiency of a power amplifier of a transmitter. Therefore, having a higher PAPR may be a bigger problem in the uplink direction where the transmitter is a user equipment (UE) having a limited battery power source.
Frequency Domain Spectrum Shaping (FDSS) may be helpful in reducing PAPR for data transmission. If FDSS is to be used for data transmission, then to be transparent, FDSS should also be used for reference signals so that channel estimation is appropriate to the data transmission.
However, methods for providing FDSS to currently accepted reference signals are not particularly effective for reducing PAPR. Therefore, alternative selection of reference signals, that provide an acceptable PAPR, when FDSS is applied to the reference signal, would be beneficial.